My favorite strategy for when people ask why I'm wearing a mask is to cough (fake obv, but I try to make it somewhat believable) and tell them I currently have covid but felt like going out anyway.
It's great because people you're not forced to keep interacting with try to get away from you ASAP with a (hopefully) newly rediscovered and more appropriate fear of covid, and people you're forced to keep interacting with will get indignant or angry and then you can clarify that you're fucking with them and if they think covid is that fucking serious that they're now mad at you, WHICH IT IS, then they should STOP FUCKING MASK SHAMING PEOPLE AND MAYBE WEAR ONE.
Almost worth the risk of unmasking near these people.